updated MARTINI and OPLSAA and added DRYMARTINI

-The MARTINI force field implementation has been incorrect for years, apparently. (It might still be, but at least MARTINI simulations now show no visually obvious signs of failure.) We obtained the MARTINI force field parameters from the EMC program instead of the original source (the cgmartini.nl web site). I am still not positive that the MARTINI force field parameters provided by EMC are compatible with the most recent MARTINI files. (If not, please let me know.) Consequently, it might be necessary to reimplement MARTINI using the original source files in the future.
-The "drymartini.lt" force field file was also added (although it has not yet been tested.)
-I fixed a (hopefully) minor problem in the OPLSAA implementation. I was using a non-bonded distance cutoff that may have been too short (10 Angstroms instead of 11). (The 1996 OPLSAA paper used an 11 Angstrom cutoff for most interactions.) Hopefully this change not significantly effect most simulation results. (Note to users: We do make mistakes, so it's never a bad idea to double-check the global settings in the force-field files we provide.)
-Finally, I added some messages that tell users what papers to cite when they run moltemplate. (Hopefully this is not too annoying.)